Sorry Mike, just saw your response. I think it would use the same parsing technique as destructuring, the left hand side would need to be post-processed. My grammar might need to be updated to make that work though.
The pattern matching strawman [1] has a note about this: Destructuring assignment is parsed as an LHSExpression but then post-processed as a Pattern(false). Note that this non-terminal represents a subset of LHSExpression. [1] http://wiki.ecmascript.org/doku.php?id=strawman:pattern_matching On Thu, May 26, 2011 at 4:06 PM, Mike Shaver <mike.sha...@gmail.com> wrote: > On Thu, May 26, 2011 at 11:54 AM, Sean Eagan <seaneag...@gmail.com> wrote: >> On Thu, May 26, 2011 at 1:43 PM, Mike Shaver <mike.sha...@gmail.com> wrote: >>> On Thu, May 26, 2011 at 11:37 AM, Sean Eagan <seaneag...@gmail.com> wrote: >>>> // ! implies non-writable, ~ implies non-enumerable >>>> // all assignment operators can be used >>>> ! a.b += c >>> >>> Legal parse today, though I'm not sure you can get runtime semantics >>> that aren't an error. >> >> Correct, I was intending for it to no longer be an error. > > I don't understand how that could work. By the time you get the > runtime error (trying to increment a boolean value), we have already > performed a property access, which can have side-effects. More > practically, an engine would have to reconstruct the original > syntactic form from the runtime result. > > addto(c, not(get(a, "b"))) > > Mike > Thanks, Sean Eagan _______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
